The present invention relates to a heated crank case ventilation system and a method for ventilating blow by gases from a crank case of an internal combustion engine.
Crankcase blow-by gases are produced when combustion gases are blown past the piston rings into the crankcase. The blow-by, which inter alia includes air, fuel, vapour, and other toxic combustion by products, increases the pressure within the engine block. These blow-by gases will interfere with engine performance if allowed to remain in the crankcase. If the blow-by gases are not relieved from the crank case it will force the oil to escape from the engine via the dip stick and/or the gaskets and the engine will thus lose lubrication.
Blow-by gases contains a certain amount of water/moisture, which can freeze to ice if the vehicle is in a freezing environment and this may stop blow by gases to escape from the crank case via a crank case ventilation system. The forming of ice can occur during standstill of the vehicle when the engine is turned of or in cold environments ice may form even when the engine is operating.
Various solutions have been proposed in the prior art to prevent freezing in the crank case ventilation systems. In U.S. Pat. No. 4,768,493 a system is disclosed in which a water jacket circulates warmed engine coolant around a positive crank case ventilation (PCV) valve. However, this system and other systems employing engine coolant have several disadvantages. The systems are too slow to work during a cold start and fail to provide heat quickly enough to prevent freezing. In addition, these systems remove capacity and related efficiency from the engine cooling system, which is generally carefully designed for the engine. Finally, these systems are relatively expensive and complex and add unnecessary weight to the vehicle.
In U.S. Pat. No. 5,970,962 electric heaters are disclosed for heating the PCV system. Electric heaters, however, drain power from the electrical system of the vehicle. The heaters are also relatively expensive and labour intensive with respect to manufacture and installation.
In addition, the above identified solutions and other solutions are not completely effective in overcoming the effects of wind chill which vary widely and which is responsive to factors such as ambient temperature, the moisture content of the environment, and the velocity of the air surrounding the crankcase ventilation system.
It is desirable to provide more effective thermal management device for a crank case ventilation system that will minimize or eliminate one or more of the above mentioned deficiencies.
According to a first aspect of the invention it is provided a crank case ventilation system (100) for ventilation of blow by gases from an internal combustion engine (106). Said system (100) comprising a crank case ventilation pipe (104) connectable with a first end (130) to the internal combustion engine (106) for receiving blow by gases from said internal combustion engine. A second end (140) of said crank case ventilation pipe (104) is provide to an air inlet pipe provided upstream of a turbo (110) and/or a super charger. Said second end of said crank case ventilation pipe (104) is provided for delivering blow by gases to said air inlet. At least a part of at least one heat pipe (114) is provided inside said crank case ventilation pipe (104). Said at least one heat pipe (114) is provided for transporting compressed air to an inlet downstream said turbo (110) and/or super charger.
An advantage with the present invention is that heat generated when making compressed air is used for heating the crank case ventilation system.
In another example embodiment said compressed air in said heat pipe is provided from said turbo or said super charger. In still another example embodiment said compressed air is generated in a separate air compressor, electrically or mechanically driven, for creating air pressure for the brakes etc in a vehicle. In still another example embodiment said compressed air is generated by a belt driven compressor or supercharger for compressing inlet air to the internal combustion engine.
The heat pipe may in another example embodiment be connected with a first end between said turbo and a charge air cooler for receiving compressed air with a pressure P1 and with a second end to a position between said turbo and said charge air cooler (112) where said pressure is lower than P1.
The heat pipe is connected with a first end between said turbo or said super charger and a charge air cooler for receiving compressed air and with a second end to a position between a charge air cooler (112) and a cylinder head.
The heat pipe is connected with a first end between said turbo or super charger and a charge air cooler for receiving compressed air and with a second end to said charge air cooler (112).
The second end of said crank case ventilation pipe is connected to an air filter (108).
According to another aspect of the present invention it is provided a method for ventilating blow by gases from a crank case of an internal combustion engine, comprising the actions of: providing a crank case ventilation pipe for receiving blow by gases from said crank case of said internal combustion engine, transporting said blow by gases from said crank case to an inlet of said internal combustion engine, where said inlet is provided upstream of a turbo and/or a super charger. Said method further comprising the action of providing at least a part of one heat pipe inside said crank case ventilation pipe, where said at least one heat pipe is provided for transporting compressed air to an inlet downstream of said turbo and/or said super charger.
In the drawings, equal or similar elements are referred to by equal reference numerals. The drawings are merely schematic representations, not intended to portray specific parameters of the invention. Moreover, the drawings are intended to depict only typical embodiments of the invention and therefore should not be considered as limiting the scope of the invention.